New sequential approach based on graph traversal algorithm to investigate cascading outages considering correlated wind farms

Abstract

One of the effective methods to reduce the risk of load shedding and its subsequent blackout is to evaluate the risk of cascading outages and detection of key links in a power system. This risk assessment is getting more complicated considering the plans for integration of high wind energy. Therefore, in this study, a new sequential time approach has been proposed to evaluate risk of cascading outages considering the high penetration of correlated wind farms. The cascading processes are investigated using the extended OPA model using the graph traversal algorithm. Therefore, the problem of non-convergence situations caused by the island formation is resolved. To deal with the future wind farms integration, a correlation is defined between them by a proposed method based on the Copula theory. The numerical results confirm that in evaluation of risk, the limited scenarios cannot always be reliable. The extended OPA model is then compared with a simple OPA to confirm the importance of islanding detection in the cascade simulation. Different aspects of cascading outages, i.e. fractional load shedding, cascade propagation level and number of line interruptions have been investigated. Finally, the impact of wind penetration and correlation of wind farms on results have been presented.